136. Single Number

description：Given a non-empty array of integers, every element appears twice except for one. Find that single one.

require：Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Example 1:

Input: [2,2,1] 
Output: 1

Example 2:

Input: [4,1,2,1,2]
Output: 4

solution

class Solution {
    public int singleNumber(int[] nums) {
        int single = nums[0];
        for (int i = 1; i < nums.length; i++) {
            single ^= nums[i]; 
        }
        return single;
    }
}

Runtime: 0 ms, faster than 100.00% of Java online submissions for Single Number.